Measles-based Zika vaccine induces long-term immunity and requires NS1 antibodies to protect the female reproductive tract in the hCD46 IFNα/β receptor knockout mice

AbstractZika virus (ZIKV) can cause devastating effects in the unborn fetus of pregnant women. To develop a candidate vaccine that can protect human fetuses, we generated a panel of live measles vaccine (MV) vectors expressing ZIKV-E and -NS1. Our MV-based ZIKV-E vaccine, MV-E2, protected mice from the non-lethal Zika Asian strain (PRVABC59) and the lethal African strain (MR766) challenge. Despite 100% survival of the MV-E2 mice, however, complete viral clearance was not achieved in the brain and reproductive tract of the lethally challenged mice. We then tested a combination of two MV-based vaccines, the MV-E2 and a vaccine expressing NS1 (MV-NS1[2]), and we observed durable plasma cell responses, complete clearance of ZIKV from the female reproductive tract, and complete fetal protection in the lethal African challenge model. Our findings suggest that NS1 antibodies are required to enhance the protection achieved by ZIKV-E antibodies in the female reproductive tract.